By using of the data of regional tectonics,reservoir loading variation,regional seismicity from 2000 to 2021,we synthetically analyzed the regional seismic spatial distribution,frequency and intensity around Xiaowan Reservoir before and after retain water,including the regional fault character,focal mechanism and seismic stress drop. The main results are as follows:①The Xiaowan reservoir locates in the cross area of Quaternary faults with complicated tectonic environment and local higher stress;②The seismicity increases obviously with the process of retain water which may make impact the bed and bank rock mass;③The seismic spatial distribution around the reservoir was controlled by regional tectonics;④The mechanism of the M5.1 earthquake is strike-slip which was mainly cause by the tectonic stress release with the water loading variation of Xiaowan reservoir.